The Moon, the natural satellite of the Earth, wasn’t formed at the same time in which was formed the Earth, but some millions of years after the Earth was formed. One of the theories of the creation of the Moon, and the one which is more accepted, is the “theory of the big impact”.
This theory considers that, the formation of the Moon, was due to an impact of a protoplanet of the solar system of the size of Mars named Tea, which, when he impacted the Earth, it took a part of land surface into the space, and all this land surface stayed orbiting the Earth. Luckily, the impact wasn’t at the middle of our planet, but in a side. For this reason, it didn’t tear off many part of the Earth’s nucleus. That’s why, nowadays, we observe that, even if the moon has a magnetic field, it’s very weak.
After many time, the different parts of the Moon that Tea took from it finished by grouping themselves to form the Moon.
The 400 kg of lunar rocks that brought the astronauts to the Earth in the different spacial missions are proves about this impact, When we analyse this lunar rocks, we see that the Moon and the Earth are made of almost the same chemical substances, including silicon, oxygen and iron. However, if we analyse the asteroid belt, the analyses indicate that there are obvious differences in the composition of rocks.
As the composition of the Earth and the Moon are so similar, the mining development in our natural satellite would only be useful if we constructed cities in it. In general, bring lunar rocks to the Earth would cot to much considering that what we can win is something that we already have. However, the lunar materials could be very useful to create directly in the satellite construction infrastructure as roads and paths, without the necessity of bringing the materials from the Earth to the Moon, as we could have them directly in the Moon.